cf_email_destinations

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations are provided, so the description carries the behavioral burden. 'List' implies a read-only operation and 'verified' hints at a filtered subset, but there is no disclosure of pagination, permission requirements, or whether unverified destinations are excluded. Useful but incomplete for a zero-annotation tool.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

A single front-loaded sentence with no filler; verb, resource, and scope appear in order of importance. Every word earns its place.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a zero-parameter list tool with an output schema, the description covers the essentials and the return shape is documented elsewhere. Missing only secondary details like pagination or result limits, which are minor here.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

The tool takes no parameters, so the baseline of 4 applies. The phrase 'under the active account' implicitly clarifies the implicit account scoping, which is the only input dimension that exists.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

Specific verb (List) plus a precise resource (verified destination email addresses for Cloudflare Email Routing) and a scope qualifier (active account). It is clearly distinguishable from siblings like cf_email_routing_rules, though it does not explicitly name that sibling to sharpen the contrast.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description states what the tool returns but gives no when-to-use guidance: no prerequisites, no indication of when to call this versus cf_email_routing_rules, and no mention of alternatives. The only contextual hint is 'under the active account'.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.